Dry cell



l utcritetl Jan. W,

BUN (Z'DIMIPANY INC., 015 YORK, N. Y., A. GURPURATIUN OF DRY tllltiliilt lite Drew/hie.

The present invention relates to dry cells end perticulurly to dry cells of that type in which it csrhonaceous rnuteriel mixed with u solid depolurizer is provided around it csrhon electrode centrally located within a Zinc conteinero It is well known in the art that the use of very linely divided graphite or other ourhonuceous muteriel hes certain advantages. The use ol lump hleclr end so-celled impelpehle gru' hits hes been suggested tor this purpose ds ee Petent No. LlGQA l-ll to U. l Burgessh However, the use oi such impel pehle grephite hes certuin drswhuclrs, since such meteriel couteins e lerge percentage o'l impurities which not only telre up yeluuhle spece in the cell but elso tend to shorten the shell lilie ol the cell end increese its internel resistunce, it is not uncommon for such impurities to constitute l(l% ol the total weight oi the grephite used.

in eccordence with the present invention such ohiectionehle impurities mey he re-- moved hy e suitelole treetment wherehy the umount oil inert meteriel in the cell is de creesed slid the shell lite oi the cell increesedi To illustrete the menuer in which. such impurities mey he removed, we shell now descrihe e treatment emhodyinp; the various ileetures oil the process ol prepering" impel pehle grephite for use in e depolurizing iniuture:

'l he urephite is tree'ted with hydrochloric ucid o2" Iltl% strength tor sererul hours, theupgh the sction mey he msterielly shortened hy hosting the solution "ti heroes the rrephite ori.grinedly lll3% ssh the 'r t-l rrephite conteius only" h.lli% ushm Mi h eel th eldest on the dry cell is well removed u eteriel is iron whose,

Application filed January 23, 19M. iterlel No. 988,056.

The graphite is then treated with normel sodium hydroxid solution wherehy the ssh further reduced to 4.18%..

"We here also used hydrochloric ecid cl other concentrations with equally good re sults end here found thet insteud ol'" hydro chloric ecid sulphuric sold or nitric ucid may he substituted. 'l l e here else :lound that oxidizing egents mey' he used with these ecids. For instance eny' soluhle perineugrenete, chlorate or uitrete or similar onidim in eg'ent muy he used to essist the notion, The treetment with ullteli mey he mode with ellreli ol' dillerent strength or by suhstitutinrr potessium hydronid tor the sodium hydrouid llllhet we cleim is: It. ll method cl propelling impelpehle graphite tor depolarizingnurtures which comprises treeting such impull'iehle runhite with an acid that 'l'orins soluble selts oil the calcium group and then with e, solution con mining en ellreliu Q A method of prepering impulpehle graphite for use in depolerinii mintureu which comprises trusting such phite with hydrochloric acid of lll% strength :lor sew erel hours, end then treetinp such l with e normel. sodium hydronid soluti .lu

ll, The method of preperingr grephite 'lor depolerieiug miritures-which consists i rst treeting' it with en sold in tphe presence oil on oxidisingegent end then with en ellrulin ll, The method oil preperiu in'ipelpehle grephite fil er depolerieiu which consists in lirst treetinp; it y te hydro chloric sold in the presenc uuy soluhle permengeouute end the-r it with e normel sodium hydrocstd solo on lln witness whereol ito suhscrihe our nurses this ltlth ueryi,

wit i. neither, i llthll tll urn till till

ll ll 

